Stereotactic System for Localizing Intracranial Targets

The CRW® stereotactic system, first released in 1988, was recently updated to focus on decreasing the steps to assemble the system while maintaining ±0.5 mm accuracy. This multi-purpose system is useful for localizing intracranial targets for precisely directing instruments. It is indicated for use in neurological procedures that require precise target localization such as craniotomies, biopsies, and functional neurosurgery. Typical instruments guided by CRW systems include biopsy forceps, radiofrequency lesioning electrodes, deep brain electrodes, recording and stimulating electrodes, hematoma evacuators, and endoscopes.

The CRW Precision™ Arc stereotactic surgery system creates a 3D coordinate model of small targets inside the body.
Stereotactic surgery systems are minimally invasive devices used to create a three-dimensional coordinate model of small targets inside the body. The first stereotactic devices for human neurosurgery were developed by American neurosurgeons Ernest A. Spiegel and Henry T. Wycis, and Swedish neurosurgeon Lars Leksell. Stereotactic neurosurgery took a major step forward in 1978, when Russell A. Brown, an American physician and computer scientist, invented a simple technique to guide stereotactic surgery with the use of CT images. This technique greatly improved the accuracy of the devices by utilizing fiducial markers in each CT image. The fiducial markers, or landmarks, gave the system the ability to determine a three-dimensional set of coordinates to guide the stereotactic device.

Brown’s invention was incorporated into the Brown-Robert-Wells (BRW) stereotactic system. The BRW system was later enhanced to become the Cosman-Robert-Wells (CRW) stereotactic system in 1988. The major update was the use of an arc-radius designed system versus the use of a polar coordinate that the BRW utilized. The arc-radius principle allows for all trajectories to pass to the target. This principle has the target remaining at a fixed distance from the probe carrier, and allows the stereotactic system the freedom to rotate around the target to obtain an optimal trajectory. This makes defining an entry point optional, and allows the clinician to utilize several approaches with the system including a Standard Approach (Probe carrier posterior), Lateral Approach (Probe carrier left or right), Posterior Fossa Approach, and a Transsphenoidal Approach.

The Integra team began designing the CRW Precision™ System by observing stereotactic surgery cases at multiple centers and interviewing the surgical teams. The interviews were used to uncover areas of improvement in the design as well as areas of the design that should be “left alone.” The design team also surveyed more than 100 functional neurosurgeons to elicit additional input into the project.

Once the prototype of the CRW Precision™ Arc was developed, the company worked with several centers to determine the practicality of the changes in order to create a final design, which was then produced and tested extensively. After the system passed all internal and external tests, Integra reviewed it again with several centers to confirm that the changes would not negatively affect clinicians’ use of the device and would be beneficial in their practices.

The final step was to introduce the product for commercial use. This was completed in June 2010, and the CRW Precision Arc has been used in a number of procedures since the launch.

This technology was done by Integra LifeSciences, Plainsboro, NJ. For more information, visit http://info.hotims.com/34452-163.

Blog: Manufacturing & Prototyping

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